Exact dosing, low material consumption

Door wax seal

Door wax seal – Fully automatic cavity preservation for corrosion prevention at welding spots and seams
Turnkey systems from Polyplan for cavity preservation of vehicle doors and hatches with sustainably optimized wax consumption

The preservation os cavities on vehicles and on add-on parts such as doors and flaps can be done by manually applying waxes or by flooding cavities in wax baths. However, both methods are no longer up to date. Manual preservation is prone to errors and can hardly be documented, while flooding wax processes do not allow targeted application and consume unnecessary amounts of wax and energy. Both processes can also result in considerable cleaning effort due to wax spillage from the cavities and wax carryover in the production line.

highly precise, drip-free, sustainable

AirLess- and AirMix-Application

The material- and energy-efficient preservation of cavities with Polyplan meets all the requirements for sustainable production in the automotive industry. The application of liquid wax with robot-guided nozzles is limited to the areas to be protected in the cavities - a typical vehicle front door can thus be completely protected against corrosion with only 4.5 g of wax material.

Minimal amount cavity sealing

Exact dosing, low material consumption - Application of preservatives into selected cavities of vehicle bodies and add-on parts

  • highly precise, resource-saving and future-proof
  • suitable for both 100% wax and water-based preservative waxes
  • even the smallest quantities can be dispensed with maximum precision
  • accurate application by robot-guided nozzle only at the areas to be protected
  • Application pattern in the application can be switched between AirLess and AirMix
  • Spray air pressure in AirMix process infinitely adjustable, metering quantity can be changed in the process
  • Application distances between 5 mm and 500 mm - beyond this on request
  • the full range of functions of the system is integrated into the production environment on a turnkey basis without interface risks and in accordance with applicable plant standards and process regulations

Complete automatic system for cavity preservation from Polyplan

System solution consisting of a wax dispenser (HD-WAX100R), a robot hose package specially developed by Polyplan, a wax jet dispensing valve (UV-WAX100R) and an application lance with integrated application nozzle, calibration tip and laser sensor VMT LineRunner OLV250 for position correction of car bodies and add-on parts.

Optionally, a material feeder (MV-WAX250L) can be integrated if no central wax supply is available.

The Task

In painted car bodies and vehicle add-on parts such as doors and flaps, welding points and seams are to be specifically wetted with liquid wax or water-based wax preservatives to prevent corrosion. The complete system for cavity preservation from Polyplan ensures (optionally) a constant supply of wax material to the application technology via a 250-liter daily container station with drum feed.

The material can be tempered and homogenized if required. In the wax dosing unit, a self-calibrating scale determines the dosing quantity with high accuracy and records the target quantity, measured quantity and weighed quantity at different discharge rates. In addition, the dosing station carries out a control check with tolerance value monitoring in definable cycles in the production process. The automatically recorded measurement series can be exported as CSV files.

Before the application of the cavity preservation begins, the laser stripe sensor performs a correction of the object position for the precise path control of the industrial robot. At the same time, a camera-based measuring system checks and corrects the position of the tool center point (TCP), measures the nozzle position and orientation and performs an online check of the wax jet orientation (AirLess application) or the spray cone geometry (AirMix application).

In the following process step, the robot inserts the application lance with the application nozzle into the cavity with high precision and coats the desired welds. Depending on the setup of the waxing station, all doors and flaps can be sealed simultaneously without additional robots having to open or hold them open. This optimizes the footprint, cycle time and energy consumption of the Polyplan complete system.


The automatic complete plant for cavity preservation rests upon on a proven plant concept, which is based on the wealth of experience of currently already 20 Polyplan plants of this type worldwide and is continuously optimized.

The configuration of the plants is tailored to the individual requirements of the application and the customer. Each plant is designed to be sustainable and at the same time complies with all relevant environmental and safety standards.

Customized plant engineering

turnkey integration into the production environment

Polyplan works with the customer to develop the right solution concept for cavity preservation and integrates the plant into the production environment on a turnkey basis according to the customer’s standards and requirements – including conveyor technology, control and IT integration or connection to fire alarm systems.

Each plant is set up at Polyplan for joint pre-commissioning with the customer before delivery.

This eliminates project risks as far as possible and ensures the shortest possible set-up and commissioning times at the final installation site.

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